FORD RANGER GEM PROBLEM

1998 Ford Ranger • 64,800 miles

I replaced the GEM to coreect the inop 4wd problem. Now I have a speedo that is out of control. When going approx. 9 miles an hour, the speedo, and data on scanner, reads in the hundreds. I was told by dealer that no flashing would be required for gem. Is there some calibration step I'm missing. Thanks for your time.

The gem don't need to be flashed. Now it could be that the sensor on the top of the rear diff may have went bad that is what tells the cruise unit that then tells the cluster the speed. If you have a digital multi meter there is a test we can do to see if that is bad.